// Copyright (c) 2011 The Chromium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

#ifndef NET_PROXY_POLLING_PROXY_CONFIG_SERVICE_H_
#define NET_PROXY_POLLING_PROXY_CONFIG_SERVICE_H_

#include "base/compiler_specific.h"
#include "base/macros.h"
#include "base/memory/ref_counted.h"
#include "base/time/time.h"
#include "net/proxy/proxy_config_service.h"

namespace net {

// PollingProxyConfigService is a base class for creating ProxyConfigService
// implementations that use polling to notice when settings have change.
//
// It runs code to get the current proxy settings on a background worker
// thread, and notifies registered observers when the value changes.
class NET_EXPORT_PRIVATE PollingProxyConfigService : public ProxyConfigService {
public:
    // ProxyConfigService implementation:
    void AddObserver(Observer* observer) override;
    void RemoveObserver(Observer* observer) override;
    ConfigAvailability GetLatestProxyConfig(ProxyConfig* config) override;
    void OnLazyPoll() override;

protected:
    // Function for retrieving the current proxy configuration.
    // Implementors must be threadsafe as the function will be invoked from
    // worker threads.
    typedef void (*GetConfigFunction)(ProxyConfig*);

    // Creates a polling-based ProxyConfigService which will test for new
    // settings at most every |poll_interval| time by calling |get_config_func|
    // on a worker thread.
    PollingProxyConfigService(
        base::TimeDelta poll_interval,
        GetConfigFunction get_config_func);

    ~PollingProxyConfigService() override;

    // Polls for changes by posting a task to the worker pool.
    void CheckForChangesNow();

private:
    class Core;
    scoped_refptr<Core> core_;

    DISALLOW_COPY_AND_ASSIGN(PollingProxyConfigService);
};

} // namespace net

#endif // NET_PROXY_POLLING_PROXY_CONFIG_SERVICE_H_
